Method and apparatus for chromatographic data processing

ABSTRACT

A chromatographic analyzer is provided for facilitating curve fitting by means of the linear least-square method for a chromatogram that contains a plurality of overlapping peaks. A chromatographic data processor executes fitting processing to each peak in an arbitrary time region having the plurality of peaks of the chromatogram starting from the front or back side of the time region, and the processed peaks are subtracted from the chromatogram in the time region so that the plurality of peaks in the chromatogram can be separated from one another.

TECHNICAL FIELD

[0001] The present invention relates to a chromatography technology suchas a liquid chromatography technology, and particularly to a dataprocessing method.

BACKGROUND ART

[0002] In chromatographs such as a liquid chromatographic analyzer, agas chromatographic analyzer or the like, a sample to be measured is letto pass through a column to be separated into components, and each ofthe separated components is detected as an output value at each elapsingtime using a photometer such as a chromatographic detector.

[0003] Signals output from the chromatographic detector are recorded astime sequential data having a time interval of several hundreds ms. Thisis what is called a chromatogram having signal intensity in the ordinateand retention time in abscissa. In general, the signal intensity isconverted to a digital value I_(j) every an arbitrary time interval(time t_(j)) to execute data processing.

[0004]FIG. 3 shows an example of a chromatogram obtained by executing abody fluid amino acid analysis.

[0005] As shown in FIG. 3, peaks of 11 components from Gly (glycine) toTyr (tyrosine) densely exist in the range of retention time from 23 to34 (min). In such a case, area-quantitative calculation isconventionally executed using a vertically dividing method in which avertical line is drawn from each minimum point between peaks, that is,what is called “a root”. However, this method produces an error as largeas several tens % to cause an incorrect result when the peaks arestrongly overlapped with each other. Therefore, when the chromatogram ofsuch a kind needs to be quantitatively analyzed in a high accuracy, ithas been general that the analyzing time is lengthened to improve theseparation degree.

[0006] On the other hand, in order to perform quantitative calculationwithout lengthening the analyzing time even if peaks are overlapped sostrongly with each other, quantitative calculation is tried to beperformed using numerical analysis in a manner like data processing.This method is, for example, a non-linear least-square method.

[0007] In the case of using the non-linear least-square method, at leastthree independent parameters (A: area, T_(R): retention time, σ:standard deviation) are used as variables in order to execute fitting ofa peak for one component. Therefore, in order to execute fitting ofpeaks for a plurality of components, it is necessary to calculate threeparameters of A_(i), T_(Ri), σ_(i) for each of the components (i).

[0008] The conventional examples of using the non-linear least-squaremethod are disclosed in Japanese Patent Application Laid-OpenNo.6-324029 and Japanese Patent Application Laid-Open No.63-151851.

[0009] These examples disclose that overlapping peaks on a chromatogramare curve-fit using a waveform function such as the Gaussian function oran EMG function (exponentially modified Gaussian function) which canexpress an asymmetric waveform of a peak. As shown in these examples,the overlapping peaks can be separated into individual peak waveforms,and the quantitative calculation can be performed by obtaining peaksizes such as a peak area and so on corresponding to a component of eachof the peaks.

DISCLOSURE OF INVENTION

[0010] However, in the conventional examples using the non-linearleast-square method, the separation of the peak waveforms is applied totwo or three overlapping peaks, but not applied to the more number ofoverlapping peaks.

[0011] The reason is that in the case of separating the overlapping peakwaveforms using curve fitting through the non-linear least-squiremethod, as the number of peak components is increased to 3, 4, 5, . . ., there occurs a phenomenon that the fitting processing is difficult tobe converged or that the separation of peaks can not correctly performed(the error is increased).

[0012] For example, in the case of the chromatogram shown in FIG. 3,when fitting is tried to the 11 components from Gly to Tyr at a time,the 33 parameters of 11×3 must be determined at a time. This is verydifficult calculation processing to the non-linear least-square method,and accordingly various kinds of techniques are necessary in order tosolve this problem. Therefore, when the curve-fitting is executed usingthe non-linear least-square method in the case of existing manyoverlapping peaks on a chromatogram, a measuring operator must specifycalculation regions (time windows) for 2 or 3 peaks seeming to beconverged one by one. This process expenses much time and much effort,and in addition, there is a problem in the reliability of thecalculation result because the regions are artificially determined.

[0013] An object of the present invention is to provide achromatographic analyzer capable of easily executing curve fitting usingthe non-linear least-square method to a chromatogram having a pluralityof overlapping peaks.

[0014] The present invention to attain the above object is characterizedby a chromatographic data processor for executing data processing of achromatogram obtained by separating a sample to be measured using acolumn and detecting the separated sample, wherein fitting processing isexecuted to each peak in an arbitrary time region having the pluralityof peaks of the chromatogram starting from the front side of the timeregion or from the back side of the time region, and the processed peaksare subtracted from the time region of the chromatogram so that theplurality of peaks in the chromatogram can be separated from oneanother.

[0015] The object, the operation and the effect of the present inventionwill be described in detail in the section of DESCRIPTION OF THEPREFERRED EMBODIMENTS to be described later.

BRIEF DESCRIPTION OF DRAWINGS

[0016]FIG. 1 is a flowchart showing fitting processing in accordancewith the present invention.

[0017]FIG. 2 is a diagram showing the outline of a chromatographicanalyzer.

[0018]FIG. 3 is a chart showing a chromatogram for 70 minutes of a bodyfluid amino acid analysis method.

[0019]FIG. 4 is a chart showing an example of a display of achromatogram in which a time window is set.

[0020]FIG. 5 is a view showing an example of a display of a dialogue boxfor setting a waveform function.

[0021]FIG. 6 is diagrams showing examples of weighting functions.

[0022]FIG. 7 is a view showing an example of a display of a dialogue boxfor selecting a weighting function and a direction of fitting.

[0023]FIG. 8 is a view showing a dialogue box for instructing executionof the fitting processing.

[0024]FIG. 9 is an illustrating chart showing a chromatogram in which afirst fitting region is set.

[0025]FIG. 10 is an illustrating chart showing the chromatogram in whicha first component is cut out.

[0026]FIG. 11 is a view showing an example of a display of a fittingresult.

[0027]FIG. 12 is a chart showing an example of graphically setting theweighting function.

BEST MODE IN WHICH THE INVENTION IS CARRIED OUT

[0028] An embodiment of the present invention will be described below.

[0029]FIG. 2 is a diagram showing the outline of a liquidchromatographic analyzer to which the present invention is applied. Aneluting solution 1 is initially pumped to a column 3 using a fluid pump2 by an instruction from a controller 5. A sample supply portion 8 isarranged between the fluid pump 2 and the column 3, and a sample issupplied from a sampler 7 containing the sample to the eluting solutionby an instruction of the controller 5. The sample is separated by thecolumn 3 to be detected using a detector 4 such as a UV detector. Achromatogram of the detected data is transmitted to the controller 5 tobe data-analyzed, and the result is displayed on a display 6 or printedby a printer 9.

[0030] Data processing in the controller 5 will be described below whenthe chromatogram of FIG. 3 is obtained as the detected result.

[0031] In the present embodiment, the data processing of thechromatogram is executed mainly according to the following procedure.

[0032] Step 1: specification of a time interval to execute fittingthereto.

[0033] Step 2: selection of a weighting pattern.

[0034] Step 3: selection of a fitting direction.

[0035] Step 4: clicking of a fitting execution button.

[0036] Step 5: displaying and outputting of the result.

[0037]FIG. 1 is a flowchart showing the detailed process of the dataprocessing of the chromatogram described above. In the presentembodiment, description will be made on a case where the fittingprocessing is executed two components by two components.

[0038] Initially, a chromatogram to be executed fitting is selected fromdetected results obtained to start the processing (100). Here, thevariable i is set to 1 (one), that is i=1.

[0039] Next, an interval of retention time to execute fitting processingthereto (a time window) is set (101). Here, the peak group of 11components from Gly to Tyr in the chromatogram of FIG. 4 is set to thetime window.

[0040] The setting of time window is performed by dragging the timeabscissa of the chromatogram displayed on the display 9 using a cursor.Otherwise, a peak starting and a peak ending the fitting may be selectedby picking the peaks Gly and Tyr of the chromatogram displayed. Further,it is possible to employ a method of inputting a starting time and anending time.

[0041] Next, a waveform function used for the fitting calculation isset. As the waveform function, for example, “Gaussian” or “EMG” may beselected. This selection can be performed by selecting a waveformfunction used using a dialogue box on the display 9 shown in FIG. 5.

[0042] Although the fitting in the present embodiment is executed twocomponents by two components, it is necessary to make the influence ofsignals of a second and later waveforms in order to accurately determinea waveform of a peak in the front side of the fitting direction, thatis, a first peak. Therefore, a weighting function shown in FIG. 6 (a) isset (103).

[0043] The weighting function is a function for weighting each of thetwo peaks. The example of FIG. 6 (a) is a function that the weight w isset to 1 (one), that is, w=1 from a peak start time 21 to a peak end(root) time 23 of the first peak, and then the weight w is linearlyslanted to be reduced from 1 to 0 from a peak start time 23 to a peakend (root) time 25 of the second peak. As the weighting function,various kinds of weighting functions may be employed. Some of theexamples are described below.

[0044]FIG. 6 (b): a weighting function having a curvilinear gradient.FIG. 6 (c): a weighting function having an S-shaped curvilineargradient. FIG. 6 (d): a weighting function having a linear gradient froma peak start point of a first peak to a peak end point of a second peak.FIG. 6 (e): a weighting function having a weight of 0.5 at an end pointof a second peak. FIG. 6 (f): a weighting function having a lineargradient from a maximum point of a second peak to an end point of thesecond peak. FIG. 6 (g): a weighting function having a linear gradientfrom a maximum point of a first peak to an end point of a second peak byparticularly attaching importance to the left-hand side of the firstpeak. The weight of 0.5 is set to an end point of the first peak (astart point of the second peak. FIG. 6 (h): a weight function having aflat weight of 0.5 from an end point of a first peak (a start point of asecond peak) to an end point of the second peak. FIG. 6 (i): a weightingfunction which is equivalent to a case without any weight.

[0045] In the concrete, the weighting function is set by displaying adialogue box shown in FIG. 7 on the display 9 and selecting a weightingpattern. Therein, by selecting an “ARBITRARY SET” and pushing an“OPTION” button, the above-described various kinds of pattern functiontype graphs shown in FIG. 6 can be set. The various kinds of patterns ofFIG. 6 are pre-stored in a memory such as a hard disk in the controller5, and can be easily read out from the memory to be used for theprocessing by being specified using a dialogue box of FIG. 7.

[0046] Next, a direction of executing fitting calculation is determined(104).

[0047] That is, describing the example of FIG. 3, it is decided whetherthe processing is executed from the front side (the Gly side) or theback side (the Tyr side). In the concrete, the setting of the directionexecuting the fitting calculation is set using the dialogue box shown inFIG. 7.

[0048] An example of executing the processing from the Gly side will bedescribed below.

[0049] By the above, setting of the conditions necessary for the fittingprocessing has been completed.

[0050] Then, a dialogue box shown in FIG. 8 is displayed after selectingan “OK” button in the dialogue box of FIG. 7, and the fittingcalculation processing is started by pushing an “EXECUTION” button.

[0051] As the calculation processing is started, number of peaks withinthe set time window is detected to be set to Imax (106).

[0052] In the concrete, inflection points inside the set time window aredetected to obtain maximum points and minimum points, and an intervalfor each of the peaks is defined by determining the maximum point as theapex and the minimum points as the end point and the starting point ofthe peak. Therein, the roots (the minimum points) of the peak and aretention time having the points are stored in relation to each other.

[0053] Next, a difference between Imax and i is calculated (107).Therein, if the difference is larger than 3 (three components), theprocessing proceeds to Process 108.

[0054] When it is judged in Process 107 that the difference is largerthan 3 (three components), a width of the weighting function set inProcess 103 is adjusted so as to meet with a width between the rootsdetected in Process 105 (108).

[0055]FIG. 9 is an illustrating chart showing a chromatogram in which aregion of first fitting processing is set. The width of the weightingfunction is adjusted so as to meet with the width of the fitting regionas shown in FIG. 9.

[0056] Next, the fitting processing is executed to the two components ofthe front side in the fitting direction (109).

[0057] The fitting processing will be described below in detail.

[0058] As described above, the Gaussian or EMG function is used as thewaveform function f(t) for the fitting. Firstly, in a case of employingthe Gaussian function, the waveform function is shown in Equation 1.$\begin{matrix}{{f(t)} = {{g_{1}(t)} + {g_{2}(t)} + {a\quad t} + b}} \\{= {{\frac{A_{1}}{\sqrt{2\quad \pi}\sigma_{1}}\exp \{ {- \frac{( {t - t_{R1}} )^{2}}{2\quad \sigma_{1}^{2}}} \}} +}} \\{{{\frac{A_{2}}{\sqrt{2\quad \pi}\sigma_{2}}\exp \{ {- \frac{( {t - t_{R2}} )^{2}}{2\quad \sigma_{2}^{2}}} \}} + {a\quad t} + b}}\end{matrix}$

(g_(i)(t): the suffix i denotes a component i.)  (Equation 1)

[0059] There, the term (at+b) denotes a base line. Though the waveformfunction becomes Equation 1 shown above because the fitting processingis executed two components by two components in the present embodiment,the fitting processing may be executed three components by threecomponents if the capability of non-linear least-square method can besecured. Of course, extension to the EMG function may be possible. In acase of employing the EMG function, the term g_(i)(t) of the waveformfunction in Equation 1 is replaced by Equation 2. $\begin{matrix}{{g_{1}^{EMG}(t)} = {\frac{A_{i}}{\sqrt{2\quad \pi}\sigma_{i}\tau_{i}}{\int_{0}^{t}{\exp \{ {{- \frac{( {t - t_{Ri} - t^{\prime}} )^{2}}{2\quad \sigma_{i}^{2}}} - \frac{t^{\prime}}{\tau_{i}}} \} \quad {t^{\prime}}}}}} & ( {{Equation}\quad 2} )\end{matrix}$

[0060] In the least-square method, each of the fitting parameters A_(i),t_(RI), σ_(i) and τ_(i) is determined so as to minimize the following S₁of Equation 3 or the following S₂ of Equation 4. There, I_(j) is asignal intensity of a measured chromatogram, j is a suffix expressingtime t_(j), and N is number of data points in a time interval. Either ofS₁ and S₂ may be used. $\begin{matrix}{S_{1} = {\sum\limits_{j = 1}^{N}\quad {w_{j}( {{f( t_{j} )} - I_{j}} )}^{2}}} & ( {{Equation}\quad 3} ) \\{S_{2} = {\sum\limits_{j = 1}^{N}\quad {w_{j}^{2}( {{f( t_{j} )} - I_{j}} )}^{2}}} & ( {{Equation}\quad 4} )\end{matrix}$

[0061] The function g_(i)(t) having a smaller value of t_(R) (that is,the earlier retention time) in the f(t) of Equation 1 obtained herecorresponds to the first peak Gly, and accordingly the waveform of thefirst component is determined (110).

[0062] Next, the waveform of the first component g_(i)(t) is subtractedfrom the original measured chromatogram to form a chromatogram cut outthe first peak Gly (111). FIG. 10 is an illustrating chart showing thechromatogram in which the first peak Gly has been cut out. It ispreferable not to subtract the base line at+b from the originalchromatogram because it does not influence the peak waveform.

[0063] Next, the variable i is incremented, and the processing isreturned to Process 107.

[0064] Then, the fitting processing for the peaks Ala and Cit isexecuted to determine the second component waveform of the second peakAla according to the same procedure as that of the fitting processingfor the first peak.

[0065] After that, the peaks Ala, Cit . . . are successively subtracteduntil the peaks for two components Leu (leucine) and Tyr in the backside end. When the remaining becomes two components (i=2), theprocessing proceeds to Process 113 to determine the peak waveforms ofthe final two components by executing the peak fitting for the twocomponents without weighting (114). Then, the peak waveforms for the twocomponents are subtracted from the original chromatogram (115) tocomplete the processing.

[0066] By the series of the processing described above, all thewaveforms in the time window have been separated from one another.Further, according to the above-described processing, since theremaining chromatogram after cutting out all the peak waveforms becomesa base line, the base line can be obtained at a time.

[0067] After completion of the above-described processing, quantitativecalculation (for example, concentration) is executed using parametersfor each of the peaks obtained by the above-described processing. Then,a display for each of the peaks (each of the components) shown in FIG.11 is displayed on the display 9 as the calculation result.

[0068] There, because the uncertainties (deviations) of the parametersfor each of the components can be obtained by the above-describedprocessing, the uncertainty of each of the measured quantitative valuescan be calculated based on the above-described uncertainties.

[0069] The point that the uncertainties of the measured quantitativevalues can be calculated is also one of the advantages of the presentembodiment. the calculation of obtaining the uncertainties of themeasured quantitative values is executed according to the errorpropagation equation.

[0070] Further, the quality of the fitting can be judged from themagnitude of the uncertainty of the measured quantitative value (it canbe said that the quality is better when the uncertainty is smaller). Forexample, the uncertainty can be used for judging quality of thecalculation result of the overlapping portion when the fittingprocessing executed from both of the front side end and the back sideend which is to be described later.

[0071] In the present invention, the above-described processingexecuting separating the peaks while the peaks are successively beingcutting out is called as “sequencing”, and the chromatographic dataprocessor for executing the sequencing is called as “a chromatographicpeak sequencer”.

[0072] Although the fitting calculation described above is executed fromthe front side end, the fitting calculation may be executed from theback side end by setting the fitting direction of the dialogue box ofFIG. 7. In this case, the function g₂(t) expressing the second peak issubtracted from the chromatogram, and the shape of the weightingfunction is reversed left to right. In the processing directiondescribed above, the peaks are cut out from the peaks having the largerretention time, that is, in order of the peaks Tyr, Leu, Ile(isoleucine) in the case of FIG. 4.

[0073] Ideally, the fitting processing may be executed from either ofthe front side and the back side. However, actually, it is preferablethat the fitting processing is executed from the both sides toward apeak having the strongest overlapping intensity. When such fittingprocessing is performed, the button “AUTOMATIC JUDGMENT” in the dialoguebox of FIG. 7 is selected.

[0074] For example, in the case of the chromatogram of FIG. 3, theforward sequencing processing is executed from the peak Gly to the peakCysthi (Cystathionine) or Ile and the backward sequencing processing isexecuted to the peak Lue or Ile because overlapping of the peaks Lue andIle is strong. By doing so, in regard to the peaks Lue and Ile, whichfitting result should be employed and determined can be judged bycomparing the appropriateness of the fitting results between the forwardprocessing and the backward processing.

[0075] Therein, the judgment can be executed by using the uncertainties(the deviations) of the fitting parameters A_(i), t_(Ri) and σ_(i)themselves as the indexes for judging the appropriateness or by usingthe statistical index χ₂ or number of repetitive calculating times forwatching the convergence rate of χ₂. Further, more comprehensivejudgment can be performed by combining these parameters. Any way, thepeak area value A_(i) needs to be accurately calculated in to executequantitative value calculation, and accordingly importance should beplaced on the uncertainty of the peak area value A_(i).

[0076] (Another Embodiment of Setting the Weighting Function)

[0077] Although the weighting function set in the above-describedprocess 102 has been set on the dialogue box, the weighting function maybe set through a program setting method in which a table method shown inTable 1 is used or through a graphical setting method in which settingis performed by displaying and superposing the weighting function on achromatogram as shown in FIG. 12. TABLE 1 Weighting program (expressingFIG. 6 (g)) Weighting Characteristic point value Shape 0 starting pointof first 1 drawing peak a vertical line horizontal line apex of firstpeak 1 gradient (straight line) root between peaks 0.5 gradient (convex)end point of second peak 0

[0078] The setting program of Table 1 shows the example of setting theweighting function of FIG. 6 (g). The weighting function is defined bythat a measurer inputs “weighting values” and “shapes”. Table 1 isdisplayed on the display.

[0079]FIG. 12 shows the method of setting the weighting function bysuperposing on the chromatogram on the display. For example, a cursor ismoved to a point near a node 31 using a pointing device, and acharacteristic point of the first peak starting point is displayed byclicking on the point. By doing so, the node 31 is determined. When thenode 31 needs to be moved, the node is picked and then released. Thatis, the node may be dragged. Next, a node 32 is determined by clickingon a point near the node 32 and vertically dragging the node 31 to apoint having a weight of 1. Therein, a vertical line is automaticallydrawn from the node 31 to the node 32 and determined. Similarly, nodes33 and 34 are determined to set the weighting function. When theweighting function needs to be changed, changing of setting can beperformed by clicking an arbitrary node to highlight the node. Further,a node can be deleted. Furthermore, a new node can be added by clickingan arbitrary point. When a line section between nodes is changed to acurvilinear line, the line section to be changed is clicked to behighlighted (the displaying color is changed), and the set attributionis changed by light-hand side clicking. Therein, concave, convex or thelike can be specified.

[0080] (Another Embodiment of Sequencing)

[0081] In the embodiment of sequencing described above, the measurementis once performed to obtain a chromatogram, and after that the dataprocessing is performed. However, it is possible to simultaneouslyexecute the sequencing processing with measuring of the sample. Anembodiment in such a case will be described below.

[0082] The simultaneous sequencing processing with measurement isprogressed as follows.

[0083] Step 1: setting of a time interval (a time window) to executefitting thereto.

[0084] Step 2: setting of a weighting pattern.

[0085] Step 3: setting of a fitting direction.

[0086] Step 4: measuring of a sample.

[0087] Step 5: executing of fitting processing.

[0088] Step 6: displaying and outputting of the result.

[0089] In Steps 1 to 3, a time program is set before startingmeasurement as shown in Table 2. A time window is set by specifying atime period from the fitting start time to the fitting end time. Inaddition, the time window may be also set by selecting a fitting startpeak and a fitting end peak as by specifying peak names “Gly” to “Tyr”.TABLE 2 Time Program Time Command Status 0.0 Waveform function Gaussian0.0 Weighting function Straight line gradient 0.0 Fitting directionAutomatic judgment 23.0 Fitting start ON 34.0 Fitting end ON

[0090] According to the chromatographic peak sequencer in accordancewith the present invention, fitting of a chromatogram having a pluralityof overlapping peaks can be automatically executed only by setting somenumber of conditions.

[0091] Further, a highly accurate base line can be calculate at the sametime. From the viewpoint of existing the highly accurate base linedetermining function, the chromatographic peak sequencer in accordancewith the present invention is considered to be an excellent dataprocessor. However, because the fitting is executed by assuming theshape of peak waveform as a shape of Gaussian or EMG function, anattention should be paid on this point when a shape of an actual peakwaveform is significantly different from the shapes of these analyticalfunctions. In such a case, it is necessary to pre-store specificwaveform functions by obtaining an isolated peak waveform for eachcomponent from a standard sample.

[0092] According to the present invention, in a chromatogram having aplurality of overlapping peaks, particularly, having three or moreoverlapping peaks, the peaks can be easily separated only by setting.some number of setting conditions. By doing so, the accuracy ofquantitative analysis and qualitative analysis can be improved. Further,the capability of determining the base line can be also improved.Furthermore, measurer's labor for the data processing can besubstantially reduced.

1-12. (canceled)
 13. A chromatographic data processor for executing dataprocessing of a chromatogram obtained by separating a sample to bemeasured using a column and detecting the separated sample, wherein thefollowing processing are repeatedly performed: specifying an arbitrarytime region, in which two or more peaks to be fitting processed exist,for said chromatogram in which plural peaks exist; applying a fittingprocessing to each peak in said arbitrary time region starting eitherfrom a front side or from a back side of said region to define theshapes of the peaks therein; and specifying a new time region other thansaid arbitrary time region to which the peak shape defining has beencompleted.
 14. A chromatographic data processor according to claim 13,wherein said fitting processing includes calculations of at least areas,retention times, and standard deviations.
 15. A chromatographic dataprocessor according to claim 13, wherein said fitting processing isexecuted by starting from both of the front and the back sides of thetime region.
 16. A chromatographic analyzer comprising a sampleseparating means for separating a sample to be measured into components;a detecting means for detecting said separated sample by said sampleseparating means; a data processing means for executing data processingby obtaining the detected result of said detecting means; and a displaymeans for displaying the data processing result, wherein said dataprocessing means comprises: means for specifying an arbitrary retentiontime region having a plurality of peaks of a chromatogram obtained asthe detected result of said detecting means; means for specifyingwhether fitting processing is executed from a front side end of or aback side end of said specified retention time region; means forspecifying a weighting function and a waveform function used in saidfitting processing, wherein a new retention time region, which has peaksother than those peaks at which the fitting processing is completed todefine their peak shapes, is displayed on said display means; and thespecification of said arbitrary retention time region, the specificationof said direction of said fitting processing, and the specification ofsaid weighting function are performed using dialogue boxes displayed onsaid display means.
 17. A chromatographic analyzer according to claim16, wherein said fitting processing includes calculations of at leastareas, retention times, and standard deviations.
 18. A chromatographicanalyzer according to claim 16, wherein the specification of saidarbitrary retention time region, the specification of said direction ofthe fitting processing and the specification of said weighting functionare performed using dialogue boxes displayed on said display meanstogether with and superimposed on the chromatogram, and wherein saidweighting function is displayed on said display means together with andsuperimposed on the chromatogram in a manner that permits an arbitraryalteration.